Belt insert strip for shot blasting machine



c. G. STRENG 3,390,487

BELT INSERT STRIP FOR SHOT BLASTING MACHINE July 2, 1968 Filed Dec. 23, 1965 w "ill 0 \nm E A P V l L .ll-lnllll. F||||||L CARL G. STRENG INVENTOR.

Mpdf

Arne/Vera United States Patent 3,390,487 BELT INSERT STRIP FOR SHOT BLASTING MACHINE Carl G. Streng, Eaglerock, Va., assignor to The H. O.

Canfield Company, Inc., Clifton Forge, Va., a corporation of Virginia Filed Dec. 23, 1965, Ser. No. 515,999 7 Claims. (CI. 51-13) ABSTRACT OF THE DISCLOSURE A resilient insert strip to be attached to each segment of the metal workpiece carrying belt of a shot blasting machine, which strip prevents wear of the metal belt due to the shot blast and removes shot from the blasting zone. The shot is removed by pockets in the leading edges of the belt insert strips, and the insert strips are provided with a cross section which tapers toward the trailing edge to facilitate the movement of the shot from one belt insert strip to the pocket of the next adjacent belt insert strip.

This invention relates to a workpiece surface finishing machine and, more particularly, to a workpiece finishing machine belt which is employed to support workpieces in a work zone in which the workpieces are simultaneously shot blasted and tumbled.

Numerous forms of belts have been employed to support workpieces in a work zone in which the workpieces are simultaneously blasted with shot from an elevated slinger and tumbled. One of these types of belts is a continuous rubber belt in which holes are provided to permit the shot to fall through the belt to an elevator in which the shot is elevated to the slinger and again fired onto the workpieces. Another form of belt is a segmented metal belt comprising a series of elongated metal sections which are linked together to move transversely relative to their long dimension.

Each of these types of belt-s has certain disadvantages. For example, the steel belt is subject to the abrading action of the shot or grit and particularly on less-than-full loads of workpieces, the grit or shot is quickly spent against the belt. Also the belt is abraded as a result of this contact. This results in two disadvantages. First, the shot is relatively expensive to replace and second, the belt wears much more rapidly when subjected to the impact of the shot. Further, metal workpieces slide freely relative to the metal belt and thus movement of the belt produces a relatively limited tumbling action for exposing all of the surfaces of the workpieces to the shot being fired. Neither of these types of belt contributes to the return of the shot to the slinger. In each instance the belts are provided with holes, slots or apertures through which the shot must fall before it is returned to the slinger by means of an elevator.

Accordingly, it is an object of this invention to provide an improved belt for a workpiece finishing machine.

Yet another object of this invention is to provide an improved belt insert for a blasting and tumbling machine.

Another object of this invention is to provide a belt which contributes to the return of the shot to the slinger to reduce the amount of shot required to perfrom the shot blasting operation.

Still another object of this invention is to provide a belt insert for a metal segmented belt in a blasting and tumbling machine in which the belt insert materially increases the tumbling action of the workpieces, increases the life of the shot or grit, and carries the major portion of the shot from the work zone.

3,390,487 Patented July 2, 1968 Briefly in accordance with aspects of this invention, a sand blasting and tumbling machine is provided with a segmented metal belt in which the segments are elongatd and are linked to move transversely of their major dimension and each belt link is provided with a resilient strip insert, which insert covers the belt and protects the belt from the abrasive action of the shot. Advantageously, the insert strips are made of resilient material preferably in the Durometer range of 50-60 and each of these strips includes pocket-means for carrying the shot from the work zone to an unloading zone where it unloads the shot onto the elevator to thus quickly return the shot to the slinger. Advantageously, these pocket-means extend transversely of the major dimension of the belt insert and have openings along the leading longitudinal edge of the belt insert strip. Also advantageously, the belts are provided with inclined surfaces which incline transversely of the belt from the leading edge downwardly and extending to the trailing edge of each strip to aid the tumbling of the workpieces and to funnel the shot into the pocket means.

These and various other objects and features of the invention will be more clearly understood from a reading of the detailed description in conjunction with the drawing in which:

FIGURE 1 is a diagrammatic side view in elevation showing portions of a finishing machine according to this invention;

FIGURE 2 is a plan view to a greatly enlarged scale of a portion of a belt insert section according to this invention; and

FIGURE 3 is a view to the same scale as FIGURE 2 of a series of metal belt sections, each having a rubber insert mounted thereon.

FIGURE 1 is a diagrammatic view in elevation of the principal operative portions of a combined shot blasting and tumbling apparatus embodying this invention. As therein depicted, the apparatus includes a continuous belt 10 and a rotating endwall 12 which define portions of a work zone 13 containing workpieces 14 which are positioned beneath a rotary shot slinger 16. The apparatus is, of course, provided with a companion endwall, not shown, which cooperates with the rotating endwall 12 and the belt 10 to define a workpiece containing work zone. The belt 10 is driven through a concave orbit in the work zone 13 and continues in a convex path until the belt returns to the work zone 13. The belt 10 is provided with pocket means, which will be subsequently described in detail, for picking up the shot in work zone 13. In passing through the convex zone immediately following the work zone, the abrasive material, such as shot, is dumped from the pocket means onto a suitable elevator 18. The elevator 118 contains a series of buckets 20 which elevate the shot or abrasive material to a suitable slide 22 on which the shot is dumped by the bucket 18. When the shot is dumped onto the slide 22 it slides downwardly into the blades of a rotating mechanical shot slinger 16 which projects the shot onto the workpieces 14.

The workpieces 14 are loaded onto the belt 10 in a loading and discharge zone 26. The belt is continually rotated by a suitable drive motor, not shown, in a direction indicated by arrows 27 and 28. The work zone endwall, such as the endwall 12, is rotated in a direction indicated by the arrow 28. After the workpieces 14 have been tumbled and subjected to the slinging shot for a sufficient time to insure surface finishing of all of the exposed areas, the drive motor for the belt 10 is stopped and driven in a reverse direction to discharge the workpieces 14 into the loading and discharge zone 26. The belt 10 is advantageously composed of a series of segmented plates each containing a flexible protective insert strip which will be subsequently described in detail.

The details of the endless belt are shown in FIG- URES 2 and 3 in which FIGURE 2 is a fragmentary plan view in a portion of the belt including a metal plate carrying a rubber or resilient insert 32. The metal plate 30 and the next successive metal plates 30a and 3% are shown in FIGURE 3 and are substantially rectangular in plan and move in a direction transversely relative to their major dimension, i.e. in the direction indicated by the arrow in FIGURE 2 and by the arrow 36 in FIG-' URE 3. Advantageously, the resilient insert 32 includes a number of elongated pockets 38 positioned with their openings 39 extending along the leading edge of the insert 32. The resilient insert 32 has a number of integral grommets such as the grommets 4t}, 41 and 42 shown in FIGURE 2, only grommet showing in FIGURE 3 in section. Each of the grommets is provided with an axially aligned hole such as the hole 45 in the resilient strip 32 which extends into the grommet 40. These holes permit a tool such as a rod to be inserted into the resilient strip behind the grommet to force the grommet into the holes 39 of plate 30.

When the resilient strip is to be inserted or attached to the metal plate, a suitable lubricant such as a liquid soap is applied to the grommet, the rod is inserted into hole 45 and pressure is applied to the rod in a direction axially aligned with hole 39. After grommet 40 enters hole 39, the outer edges of the head of the grommet return to their unstressed position and the perpendicular edges or flanges such as flange 44 snugly engages the lower surface of plate 30. The resilient strip 32 includes a main body 46 extending substantially parallel to the plate 30 and having oppositely disposed perpendicularly projecting feet such as the feet 47 and 48 which extend the entire length of the strip 32. The leading edge 49 of the strip 32 includes a top portion 50 which has a thickness substantially equal to the thickness of the leading portion of the main body portion 46 to give the resilient strip 32 sufficient resilience to support the articles or the workpieces without permitting the workpieces to close the leading edge apertures such as the aperture 39. Thus the upper edge 51 of the portion 50 is substantially parallel to the surfaces of the leading edge recess 39. Subsequent to this surface 51, the resilient strip 38 has a surface 52 which angles slightly downwardly toward the trailing edge 55. Inclined surface 51 connects with an inclined surface 53 which extends to the trailing edge 55 and surface 53 is inclined more sharply than the inclined surface 52. The combination of the stepped leading edge 49, surface 51, the slightly inclined surface 52 and the more steeply-inclined surface 53 acts to accentuate the tumbling action of the workpieces as the resilient strips move to the left as viewed in FIGURE 3 through the U-shaped work zone 13 shown in FIGURE 1. Further, the combination of the flat and two inclined surfaces aid in the movement of the shot or other abrasive material toward the recess in the leading edge of the next subsequent strip such as the recess 39a in the strip 32a. It is to be noted that the edges of the metal segments 30, 30a, 3% are practically in abutting relationship.

In one illustrative embodiment, the resilient strip 32 is formed in lengths approximately 18 inches long and approximately 4 inches in width. The leading edge has a total heighth of 1%.; inches and the pocket means has an opening approximately of an inch in heighth. The width of the top flat surface 51 is approximately of an inch. The first inclined surface 52 is inclined at an angle of approximately 10 and has a width of approximately 1% inches and the second or more steeply-inclined surface 53 is inclined at an angle of the order of 19 and has a width of the order of 1 /2 inches. The heighth of the trailing edge 55 is A of an inch and the flanges 47, 48 support the main body 46 of the strip 32 approximately A of an inch above the point at which the flanges contact the metal strip 30. The'grommet 40 and grommets 41 and 42 are of identical size and have heads which have an outer diameter of 1 inch. These grommets have a diameter of of an inch where the grommets extend through the plates 30. The apertures such asaperture 45 are positioned on a line 1% inches from the leading edge of the flexible strip 32. The depth of the apertures, such as the aperture 45, are of the order of 1 inch. The pocket means, such as the pocket 39, are substantially rectangular in cross sectioned their entrance and extend transversely of the strip 32 toward the trailing edge of the strip, a distance of the order of 1% inches and just prior to the terminal edge have a downwardly sloping upper roof such that the top portion of the leading edge of the resilient strip is supported by the increased thickness of resilient material in this area. The metal segments 30 extend a very small distance transversely beyond the resilient strip 32; for example, the projection may be of the order of of an inch on each side or edge of the resilient strip 32.

From the foregoing explanation, it is apparent that the rubber insert strips prolong the life of the belt by preventing the abrasive shot from damaging the metal segments and are particularly effective when less than full loads of workpieces are positioned in the work zone 13. Further, the resilient strips will absorb the impact of the shot from the slinger 16 and thus prolong the life of the shot. Also advantageously, the pockets 39 in the leading edges of the resilient strips will quickly return the major portion of the abrasive material such as shot to the rotary slinger by way of the elevator 18 and slide 22.

In accordance with the patent statutes, the principles of the present invention may be utilized in various Ways, numerous modifications and alterations being contemplated, substitution of parts and changes in construction being resorted to as defined, it being understood that the embodiment shown in the drawings is given merely for purposes of explanation and illustration without intending to limit the scope of the claims to the specific details disclosed.

I claim:

1. In a combination shot blasting and article tumbling machine having shot slinging means, a segmented continuous metal belt, drive means for driving said belt through a work zone which is concave in cross-section,

and is positioned to receive shot from said slinging means, a plurality of elongated resilient strips, each fastened to an individual segment of said belt, to be moved transversely of its longer dimension, each strip including pocket means for picking up shot in the work zone and for discharging said shot in a zone remote from said work zone and means for moving said shot from said remote zone to said slinging means.

2. The combination according to claim 1 wherein said pocket means include pockets having depth transversely ofsaid strip, said pockets having a plurality of openings along the leading edge of said strip.

3. The combination according to claim 1 wherein each of said strips includes fastening means for fastening said strips to said belt.

4. The combination according to claim 1 wherein each of said strips includes transversely inclined surface means inclined downwardly away from said leading edge and extending to the trailing edge for aiding the tumbling of said workpieces and for aiding the movement of shot from one strip to the pocket means of the next successive strip on said belt.

5. A resilient strip to be attached to an endless belt in a shot blasting and tumbling machine having a blasting zone in which shot are thrown toward workpieces, comprising:

an elongated body of resilient material to be mounted on said belt to move in a direction transverse the major dimension of said body through a shot blasting zone and having a leading edge and a trailing edge;

pocket means in said strip having apertures along said leading edge of said strip and extending transversely of said strip for carrying shot from said blasting zone; and

means for fastening said strip to said belt.

6. A resilient strip according to claim 5 wherein said body, when viewed in side elevation, has at least one surface inclined downwardly toward the trailing edge to facilitate the tumbling of workpieces and to drain the shot toward the trailing edge of said body.

7. A resilient strip according to claim 5 formed of material having a Durometer range of 50-60.

References Cited UNITED STATES PATENTS Camp 198-153 Spalding 198153 X Turnbull 5113 Keefer 5113 Turnbull 51-13 Holz 198-189 LESTER M. SWINGLE, Primary Examiner. 

